DAB tuner: Control

WARNING: This page is about a different car, the 2013 BMW X5, 2012 BMW X5, and 2011 BMW X5. However, it is still accessible from the selected car via links, so may be relevant.

The quantity of recirculated exhaust gas influences the mass of the fresh air drawn in: The more exhaust gas is recirculated, the less fresh air is drawn in. The mass of fresh air that passes through the engine at any point on the performance curve when the EGR is switched off is a known quantity. Thus the reduction in the mass of fresh air drawn in due to exhaust gas recirculation is a measure of the quantity of exhaust gas recirculated. During operation, the duty factor on the pressure converter is controlled in such a way that the specified fresh air mass for the operating point concerned is drawn in.

The DDE control module calculates a specified fresh air mass figure for every operating point from the following variables:

Engine speed
Injection volume
Coolant temperature
Atmospheric pressure
Intake air temperature
Reduction in exhaust gas recirculation by idling for longer than 5 min

Exhaust gas recirculation calibration (service function) also affects the specified figure for exhaust gas recirculation. The causes of cutoff of the exhaust gas recirculation in operation can be read out of the control module. The causes of the cutoff indicate whether EGR control is active or whether it has been deactivated due to one of the conditions listed below.